tests-mbed_drivers-timerevent: perform test only if USTICKER support is enabled.
tests-mbed_drivers-timerevent: perform test only if USTICKER support is enabled.

betzw/mbed-os,andcor02/mbed-os,betzw/mbed-os,betzw/mbed-os,andcor02/mbed-os,kjbracey-arm/mbed,c1728p9/mbed-os,andcor02/mbed-os,mbedmicro/mbed,betzw/mbed-os,mbedmicro/mbed,betzw/mbed-os,c1728p9/mbed-os,kjbracey-arm/mbed,c1728p9/mbed-os,c1728p9/mbed-os,kjbracey-arm/mbed,c1728p9/mbed-os,kjbracey-arm/mbed,andcor02/mbed-os,betzw/mbed-os,c1728p9/mbed-os,mbedmicro/mbed,mbedmicro/mbed,andcor02/mbed-os,andcor02/mbed-os,mbedmicro/mbed